Dynamic vitrimer-like polydimethylsiloxane elastomers with tailored crosslinking networks for wearable sensors and temperature-responsive devices

摘要

• Vitrimer-like PDMS with three mixed crosslinking networks are developed. • Disulfide-bond crosslinking elastomers exhibit superior mechanical properties and self-healing behaviors. • The self-healing properties can be optimized via the PDMS molecular weight and the variety and density of dynamic bonds. • PDMS-CNTs composites display outstanding properties, showing high promise for wearable devices and temperature sensors. Vitrimers uniquely combine the advantages of thermosetting and thermoplastic polymers, yet optimizing their mechanical properties through crosslinking network design remains an open challenge. Herein, vitrimer-like polydimethylsiloxane (PDMS) elastomers featuring mixed crosslinking networks have been developed via a thiol-ene click reaction between tetra-thiol monomers and acrylate-terminated monomers (acrylate-terminated PDMS(A-PDMS x ) and acrylate-terminated disulphide (MA-SS-MA)). The resulting networks comprise permanent crosslinking provided by A-PDMS x , disulfide-bond dynamic crosslinking derived from MA-SS-MA, and hydrogen-bond dynamic crosslinking based on urethane, ester, and free hydroxy-terminated PDMS. The elastomers exhibit increased tensile strength (1.95 MPa), a remarkable elongation at break (570 %), improved toughness (1.17 MJ m −3 ), as well as excellent self-healing properties tunable through the PDMS molecular weight and the variety and density of dynamic bonds. Furthermore, its composites with carbon nanotubes display outstanding flexibility, electrical conductivity, thermal conductivity, and self-healing properties, positioning them as ideal candidates for next-generation wearable electronics, soft robotics, and advanced temperature sensors.